The invention relates to improvements in apparatus for ascertaining the magnitude of stresses upon bearings, such as antifriction ball or roller bearings which are used in the rolls of calenders and like machines.
Commonly owned U.S. Pat. No. 4,625,637 granted Dec. 2, 1986 to Pav et al. discloses a roll assembly for use in calenders and like machines. The magnitude of stresses upon bearings between the end portions of a stationary carrier and a deformable cylindrical shell which is rotatable relative to and surrounds the carrier is ascertained by an apparatus which employs several sensors in the form of force, pressure, displacement or distance transducers which are recessed into the peripheral surface of the carrier or into the internal surface of the inner race of the respective bearing. An evaluating circuit is provided to process signals which are supplied by the transducers. The patented apparatus operates satisfactorily; however, the cost of such apparatus is relatively high and the sensors must be inspected, repaired and/or replaced at rather frequent intervals because they are often subjected to pronounced stresses. Moreover, the laying of conductors for transmission of signals from the transducers to the evaluating circuit is a complex, costly and time-consuming procedure. Replacement of a transducer, or of two or more transducers, takes up much time and entails a prolonged deactivation of the machine.